The IFERROR function was introduced in 2007 and later, this will have to be re-written using the Excel 2003 syntax =IF(ISERROR(...))
=IF(ISERROR(INDEX(List,MATCH(0,INDEX(COUNTIF(G$1:G1,List),0),0))),"",INDEX(List,MATCH(0,INDEX(COUNTIF(G$1:G1,List),0),0))

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
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Just applying a bit of logic and it would seem that it is currently circular.

Your list in column A is populated by a dropdown based on previous entries in column A; but you don't want duplicates in the dropdown, so can only choose items that have already been listed.

Or do you want to be able to add items and thus have them in the dropdown for future entries but not duplicated.

See attached.

However, this method does throw a slight problem; highlighted by the two entries of New York. I have added them both manually to the list but deliberately mistyped the first entry, omitting the space. This has now appeared in the dopdown list options twice.

The formulae in column G refer to the List range and extract single items, but not in Alphabetical order. If you look at the cells below New York, the formulae go down to row 20, the same as the original list.

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Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

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